Rebuilding my '55 Chevy 1 1/2 ton truck. All new factory replacement wiring. Everything works, lights, horn, radio, etc. What's annoying though is the ammeter (I'm pretty sure it's an ammeter) is jumping from charge to discharge, when first started is shows positive charge for a minute or two until the system is charged, then it shows discharge for a while then charge. The other night, it was the first time I had the lights on after dark you could see it in the headlights, brighter-dimmer. If I would have been driving at night people would have thought I was flashing my lights at them. Any thoughts? Generator? Voltage regulator? Battery? Whew, finally starting to look like a truck again!